Medium-range remote access and control of a motor vehicle can be achieved with a user-carried RF transceiver such as a so-called “smart key fob”. For example, the fob can be used not only to gain entry to the vehicle, but also to start the engine, access vehicle status information, and so forth. Similar functionality can be achieved with a specially programmed personal communication device such as a cell phone or PDA, as described for example in the U.S. Pat. No. 6,970,703 to Fuchs et al. and the U.S. Pat. No. 7,224,262 to Simon et al., both of which are incorporated herein by reference.
Both of the above-described approaches have drawbacks. For example, smart key fobs tend to become both too large and too expensive when human-machine interface (HMI) devices such as keypads and displays are integrated into the fob. And requiring the vehicle operator to use a specially programmed personal communication device and to pay for cellular network service is also undesirable. Accordingly, what is needed is an improved and lower-cost way of achieving medium-range remote communication and control for a vehicle.